1. Field of the Invention
The present invention relates to an exposure apparatus, a temperature regulating system, and a device manufacturing method.
2. Description of the Related Art
An exposure apparatus is used to manufacture an electronic device such as a semiconductor device or liquid crystal display device. The exposure apparatus projects the pattern of a reticle onto a substrate coated with a photosensitive agent (photoresist), thereby exposing the photosensitive agent.
The exposure apparatus includes a plurality of units. A temperature-regulated fluid is supplied to the units to temperature-regulate them (see Japanese Patent Laid-Open No. 2005-136004).
FIG. 2 is a block diagram showing the schematic arrangement of a conventional temperature regulating system. A liquid pressurized by a pump 101 is temperature-regulated by a temperature regulating unit 102, and supplied to units 105a to 105e via a circulating line 120 and branching portion 107.
Flow rate regulating valves 104a to 104e and flow rate sensors 106a to 106e are inserted into the flow passages of the units 105a to 105e. The flow rate regulating valves 104a to 104e control the flow rates of fluid components flowing through the units 105a to 105e, so that each of the flow rate sensors 106a to 106e indicates a target value. At this time, a shutoff valve 103g connected to a bypass line 129 is fully closed, and shutoff valves 103f and 103h connected to the circulating line 120 and a circulating line 121 are fully open.
The fluid components remove heat generated by the units 105a to 105e, and merge with each other at a confluence portion 108. The fluid components then return into a tank 100 via the circulating line 121. A flow rate sensor 106f for detecting the total flow rate of the fluid is connected to the circulating line 121.
Assume that liquid supply to only a unit to be maintained or replaced is stopped. Since the conventional temperature regulating system is a parallel system, it loses the flow rate balance and therefore supplies a liquid in larger amounts than before to other units. In this case, the pressures that act on the entrances of the other units rise, so they may exceed withstand pressures.
In the maintenance work or replacement work, the pump 101 must be stopped or all the fluid must be bypassed via the bypass line 129 by closing the shutoff valves 103f and 103h and opening the shutoff valve 103g. 